Trophallaxis is the transfer of food and glandular secretions from one individual to another. The ant burps a drop of liquid from its mouth, and its relatives drink it. This is stomodal trophallaxis. Keepers are accustomed to calling it simply “trophallaxis”.

Proctodeal trophallaxis is the opposite phenomenon, because the transfer of food also occurs from the end opposite the mouth! This is the release of nutrients through the anus.
Not all social insects share food in the same way. Ants, for example, still have a predominance of stomodeal trophallaxis, while termites have a predominance of proctodeal trophallaxis (they process wood most completely only after it has passed through many stomachs).